U.S. patent application number 13/624543 was filed with the patent office on 2014-03-27 for transition duct for use in a turbine engine and method of assembly.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to Scott Michael Carson, Brian David Keith, Joseph Machnaim.
Application Number | 20140086739 13/624543 |
Document ID | / |
Family ID | 49081015 |
Filed Date | 2014-03-27 |
United States Patent
Application |
20140086739 |
Kind Code |
A1 |
Machnaim; Joseph ; et
al. |
March 27, 2014 |
TRANSITION DUCT FOR USE IN A TURBINE ENGINE AND METHOD OF
ASSEMBLY
Abstract
A transition duct for use in a turbine engine is provided. The
transition duct includes a radially inner wall and a radially outer
wall positioned about the radially inner wall defining a flow
passage therebetween. The radially outer wall extends and is
contoured from an upstream end to a downstream end of the
transition duct. As such, the slope of the radially outer wall
increases from the upstream end to a predetermined axial location
and decreases from the predetermined axial location to the
downstream end.
Inventors: |
Machnaim; Joseph;
(Bangalore, IN) ; Keith; Brian David; (Cincinnati,
OH) ; Carson; Scott Michael; (Cincinnati,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
Schenectady |
NY |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
49081015 |
Appl. No.: |
13/624543 |
Filed: |
September 21, 2012 |
Current U.S.
Class: |
415/220 ;
29/889.22; 60/262; 60/269 |
Current CPC
Class: |
F04D 29/547 20130101;
Y10T 29/49323 20150115; F01D 9/02 20130101; B23P 11/00 20130101;
F02K 3/065 20130101 |
Class at
Publication: |
415/220 ; 60/262;
60/269; 29/889.22 |
International
Class: |
F02K 3/065 20060101
F02K003/065; B23P 11/00 20060101 B23P011/00; F04D 29/54 20060101
F04D029/54 |
Claims
1. A transition duct for use in a turbine engine, the transition
duct comprising: a radially inner wall; and a radially outer wall
positioned about said radially inner wall defining a flow passage
therebetween, said radially outer wall extends and is contoured
from an upstream end to a downstream end of the transition duct
such that a slope of said radially outer wall increases from said
upstream end to a predetermined axial location and decreases from
the predetermined axial location to said downstream end.
2. The transition duct in accordance with claim 1 further
comprising a fairing that extends radially between said radially
inner wall and said radially outer wall within said flow passage,
wherein said fairing comprises an aerodynamic cross-sectional
shape.
3. The transition duct in accordance with claim 2, wherein the
predetermined axial location corresponds to an axial location of a
thickest cross-sectional portion of said fairing such that a
maximum slope of said radially outer wall is at the predetermined
axial location.
4. The transition duct in accordance with claim 1, wherein the
slope of said radially outer wall increases from about 0.degree. at
said upstream end to greater than about 40.degree. at the
predetermined axial location.
5. The transition duct in accordance with claim 1, wherein said
radially outer wall comprises a maximum wall slope at the
predetermined axial location, the maximum wall slope from about
40.degree. to about 50.degree..
6. The transition duct in accordance with claim 5, wherein the
slope of said radially outer wall decreases from the maximum wall
slope to no less than about 30.degree. at said downstream end.
7. The transition duct in accordance with claim 1, wherein said
radially inner wall extends and is contoured from said upstream end
to said downstream end such that the transition duct has a larger
cross-sectional area at said downstream end than said upstream
end.
8. The transition duct in accordance with claim 7, wherein the
transition duct comprises an area ratio of greater than about
1.35.
9. The transition duct in accordance with claim 1, wherein the
transition duct comprises a radius ratio of greater than about
2.0.
10. A turbine assembly comprising: a high-pressure turbine
positioned about a centerline axis at a first radius from the
centerline axis; a low-pressure turbine positioned about the
centerline axis at a second radius from the centerline axis that is
greater than the first radius; and a transition duct coupled
between said high-pressure turbine and said low-pressure turbine,
said transition duct comprising: a radially inner wall; and a
radially outer wall positioned about said radially inner wall
defining a flow passage therebetween, said radially outer wall
extends and is contoured from an upstream end to a downstream end
of the transition duct such that a slope of said radially outer
wall increases from said upstream end to a predetermined axial
location and decreases from the predetermined axial location to
said downstream end.
11. The turbine assembly in accordance with claim 10, wherein said
transition duct facilitates reducing flow separation of fluid
channeled through said flow passage.
12. The turbine assembly in accordance with claim 10, said radially
inner wall extends and is contoured from said upstream end to said
downstream end such that the transition duct has a larger
cross-sectional area at said downstream end than said upstream
end.
13. The turbine assembly accordance with claim 10, wherein the
slope of said radially outer wall increases from about 0.degree. at
the upstream end to greater than about 40.degree. at the
predetermined axial location.
14. The turbine assembly in accordance with claim 10, wherein said
radially outer wall comprises a maximum wall slope at the
predetermined axial location, the maximum wall slope from about
40.degree. to about 50.degree..
15. The turbine assembly in accordance with claim 14, wherein the
slope of said radially outer wall decreases from the maximum wall
slope to no less than about 30.degree. at said downstream end.
16. The turbine assembly in accordance with claim 10, wherein each
of said radially inner wall and said radially outer wall extend
circumferentially about the centerline axis such that a
substantially annular flow passage is defined therebetween.
17. A method of assembling a transition duct for use in a turbine
assembly, the transition duct comprising a radially inner wall and
a radially outer wall, said method comprising: positioning the
radially outer wall about the radially inner wall such that a flow
passage is defined therebetween; extending the radially outer wall
from an upstream end to a downstream end of the transition duct;
and contouring the radially outer wall from the upstream end to the
downstream end such that a slope of the radially outer wall
increases from the upstream end to a predetermined axial location
and decreases from the predetermined axial location to the
downstream end.
18. The method in accordance with claim 17, wherein contouring the
radially outer wall further comprises increasing the slope of the
radially outer wall from about 0.degree. at the upstream end to
greater than about 40.degree. at the predetermined axial
location.
19. The method in accordance with claim 17, wherein contouring the
radially outer wall further comprises contouring the radially outer
wall such that a maximum wall slope is located at the predetermined
axial location, the maximum wall slope from about 40.degree. to
about 50.degree..
20. The method in accordance with claim 19, wherein contouring the
radially outer wall further comprises decreasing the slope of the
radially outer wall from the maximum wall slope to no less than
about 30.degree. at the downstream end.
Description
BACKGROUND OF THE INVENTION
[0001] The field of the disclosure relates generally to turbine
engines and, more specifically, to a transition duct for use in a
turbine engine.
[0002] At least some known gas turbine engines include a forward
fan, a core engine, and a low-pressure turbine (LPT) coupled
together in serial flow relationship. The core engine includes at
least one compressor, a combustor, and a high-pressure turbine
(HPT). More specifically, the compressor and HPT are coupled
through a shaft to define a high-pressure rotor assembly. Air
entering the core engine is compressed, mixed with fuel, and
ignited to form a high energy gas stream. The high energy gas
stream is directed through the HPT to rotatably drive the HPT such
that the shaft rotatably drives the compressor. The high energy gas
stream is then channeled towards the LPT coupled downstream from
the HPT via a transition duct.
[0003] Generally, a known HPT has a smaller radius than a known
LPT. As such, known transition ducts coupled between the HPT and
the LPT have an "S" shaped cross-section to facilitate flow
communication therebetween. Generally, it is desirable to
transition from the smaller-radius high-pressure turbine to the
larger-radius low-pressure turbine within as short an axial
distance as possible. Such a quick transition with a shorter
transition duct facilitates reducing the weight of the overall
turbine assembly and facilitates increasing the performance of the
engine. However, using a shorter transition duct with aggressive
curvature may lead to flow separation at the boundary layers of the
transition duct walls.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one aspect, a transition duct for use in a turbine engine
is provided. The transition duct includes a radially inner wall and
a radially outer wall positioned about the radially inner wall
defining a flow passage therebetween. The radially outer wall
extends and is contoured from an upstream end to a downstream end
of the transition duct. As such, the slope of the radially outer
wall increases from the upstream end to a predetermined axial
location and decreases from the predetermined axial location to the
downstream end.
[0005] In another aspect, a turbine assembly is provided. The
turbine assembly includes a high-pressure turbine, a low-pressure
turbine, and a transitions duct coupled therebetween. The
high-pressure turbine is positioned about a centerline axis at a
first radius from the centerline axis and the low-pressure turbine
is positioned about the centerline axis at a second radius from the
centerline axis that is greater than the first radius. The
transition duct includes a radially inner wall and a radially outer
wall positioned about the radially inner wall defining a flow
passage therebetween. The radially outer wall extends and is
contoured from an upstream end to a downstream end of the
transition duct. As such, the slope of the radially outer wall
increases from the upstream end to a predetermined axial location
and decreases from the predetermined axial location to the
downstream end.
[0006] In yet another aspect, a method of assembling a transition
duct for use in a turbine assembly is provided. The transition duct
includes a radially inner wall and a radially outer wall. The
method includes positioning the radially outer wall about the
radially inner wall such that a flow passage is defined
therebetween and extending the radially outer wall from an upstream
end to a downstream end of the transition duct. The method also
includes contouring the radially outer wall from the upstream end
to the downstream end such that a slope of the radially outer wall
increases from the upstream end to a predetermined axial location
and decreases from the predetermined axial location to the
downstream end.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a cross-sectional view of an exemplary turbine
engine.
[0008] FIG. 2 is a perspective view of an exemplary turbine center
frame that may be used in the turbine engine shown in FIG. 1.
[0009] FIG. 3 is a perspective view of an exemplary fairing that
may be used with the turbine center frame shown in FIG. 2.
[0010] FIG. 4 is a schematic cross-sectional view of the transition
duct formed from the fairing shown in FIG. 3.
[0011] FIG. 5 is a normalized view of the local wall slope for an
exemplary radially outer wall that may be used in the transition
duct shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Embodiments of the present disclosure relate to the use of a
transition duct to couple the discharge outlet of a high-pressure
turbine (HPT) to the inlet of a low-pressure turbine (LPT) in a gas
turbine engine. Generally, it is desirable to quickly transition
from the smaller-radius HPT to the larger-radius LPT with a
transition duct to channel fluid flowing therethrough. Transition
to the larger radius facilitates improving LPT performance and
efficiency. However, using a transition duct that has a shorter
axial length with aggressive outer wall slope may lead to boundary
layer flow separation of the fluid flowing therethrough.
Furthermore, known transition ducts include struts and/or fairings
extending therethrough that are used to support the turbine center
frame. These known struts and fairings disrupt the flow of fluid
flowing through the transition duct. Accordingly, flow separation
may also occur on the fairing or at the interface between the
fairing and the outer wall, i.e. at the location where both the
boundary layers interact.
[0013] As such, in the exemplary embodiment, the transition duct
described herein facilitates reducing flow separation of fluid
channeled from the HPT to the LPT. More specifically, the
transition duct includes an aggressive outer wall slope from the
duct inlet to a predetermined axial location in the transition
duct, and reduced outer wall slope from the predetermined axial
location to the duct discharge. In the exemplary embodiment, the
predetermined axial location is the thickest portion (T.sub.max
location) of the aerodynamic strut fairing. Accordingly, the
transition duct described herein facilitates improving LPT
performance and efficiency by controlling the boundary layer
interaction between the outer wall of the transition duct and the
strut fairing.
[0014] FIG. 1 is a schematic view of an exemplary gas turbine
engine 10 that includes a fan assembly 12 and a core engine 13
including a high pressure compressor 14, a combustor 16, and a
high-pressure turbine (HPT) 18. Engine 10 also includes a
low-pressure turbine (LPT) 20 and a turbine center frame/transition
duct 100 coupled between HPT 18 and LPT 20. Fan assembly 12
includes an array of fan blades 24 that extend radially outward
from a rotor disk 26. Engine 10 has an intake side 28 and an
exhaust side 30. Fan assembly 12 and LPT 20 are coupled by a
low-speed rotor shaft 31, and compressor 14 and HPT 18 are coupled
by a high-speed rotor shaft 32.
[0015] Generally, during operation, air flows axially through fan
assembly 12, in a direction that is substantially parallel to a
centerline 34 that extends through engine 10, and compressed air is
supplied to high pressure compressor 14. The highly compressed air
is delivered to combustor 16. Combustion gas flow (not shown) from
combustor 16 drives turbines 18 and 20. HPT 18 drives compressor 14
by way of shaft 32 and LPT 20 drives fan assembly 12 by way of
shaft 31.
[0016] As used herein, the term "axial", "axially", or "coaxially"
refers to a direction along or substantially parallel to centerline
34. Furthermore, as used herein, the term "radial" or "radially"
refers to a direction substantially perpendicular to centerline
34.
[0017] FIG. 2 is a perspective view of an exemplary turbine center
frame 100, and FIG. 3 is a perspective view of a fairing 200 that
may be used with the turbine center frame 100. Turbine center frame
100 includes a central hub 102 and an outer ring 104 positioned
about central hub 102. In the exemplary embodiment, central hub 102
and outer ring 104 are coupled together with struts 106 extending
radially therebetween.
[0018] Furthermore, in the exemplary embodiment, turbine center
frame 100 uses a plurality of fairings 200 to protect turbine
center frame 100 from a hot gas path environment. Fairing 200
includes a leading edge 202, a T.sub.max location 204, and a
trailing edge 206. In the exemplary embodiment, fairing 200 has an
aerodynamic cross-sectional shape. As such, T.sub.max location 204
corresponds to the axial location of the thickest portion of
fairing 200. For example, in one embodiment, T.sub.max location 204
is located from leading edge 202 at about 30% to about 45% the
length 316 (not shown in FIG. 2) of fairing 200, or more
specifically about 33% of length 316. In one embodiment, a
plurality of fairings 200 are arranged about central hub 102 and
include a radially outer shroud 208 and a radially inner shroud 210
coupled thereto. As such, a substantially annular transition duct
300 is formed by shrouds 208 and 210 about centerline 34 (shown in
FIG. 1).
[0019] FIG. 4 is a schematic cross-sectional view of transition
duct 300 and a transition duct 400, and FIG. 5 is a normalized view
of the local wall slope for a radially outer wall 302 that may be
used in transition duct 300. Although transition duct 300 will be
discussed in further detail, it should be understood that the same
may apply to transition duct 400. In the exemplary embodiment,
transition duct 300 includes a radially inner wall 304 formed from
radially inner shroud 210 (shown in FIG. 3) and radially outer wall
302 formed from radially outer shroud 208 (shown in FIG. 3).
Radially outer wall 302 is positioned about radially inner wall 304
such that a flow passage 306 is defined therebetween.
[0020] In some embodiments, radially outer wall 302 and radially
inner wall 304 extend and are contoured from an upstream end 310 of
transition duct 300 to a downstream end 320 of transition duct 300
to facilitate coupling HPT 18 in flow communication with LPT 20
(shown in FIG. 1). More specifically, the curvature and slope of
radially outer wall 302 are controlled to facilitate reducing flow
separation within transition duct 300. For example, in the
exemplary embodiment, radially outer wall 302 includes an
aggressive outer wall slope from upstream end 310 to a
predetermined axial location 308, and reduced slope from
predetermined axial location 308 to downstream end 320 of
transition duct 300. As used herein, the term "slope" refers to the
angle, at any given point, of radially outer wall 302 and radially
inner wall 304 with respect to centerline 34.
[0021] Accordingly, in the exemplary embodiment, radially outer
wall 302 at upstream end 310 is located at a first radial distance
312 from centerline 34 (shown in FIG. 1), and radially outer wall
302 at downstream end 320 is located at a second radial distance
322 from centerline 34. Second radial distance 322 is greater than
first radial distance 312 such that a AR 332 is present
therebetween. Furthermore, in the exemplary embodiment, transition
duct 300 includes a height 314, length 316, a first area 318 at
upstream end 310, and a second area 328 at downstream end 320. As
such, controlled radially outer wall 302 diffusion is applicable
when transition duct 300 has radius ratio (AR 332/height 314) of
greater than about 2.0, a length 316/height 314 ratio of between
about 2.75 and 4.50, and an area ratio (second area 328/first area
318) of greater than about 1.35.
[0022] In the exemplary embodiment, the contouring and slope of
radially outer wall 302 facilitates controlling the boundary layer
interaction at radially outer wall 302 and at fairing 200. For
example, radially outer wall 302 is configured to facilitate
preventing flow separation at radially outer wall 302 caused by
aggressive outer wall slope beyond predetermined axial location
308, and/or flow separation caused by the presence of fairing 200
within flow passage 306. More specifically, in the exemplary
embodiment, the slope of radially outer wall 302 increases from
upstream end 310 to predetermined axial location 308, and decreases
from predetermined axial location 308 to downstream end 320. In the
exemplary embodiment, the region downstream from predetermined
axial location 308 corresponds to a region within transition duct
300 that may have a high probability of flow separation as fairing
200 diffuses the flow in the circumferential direction.
[0023] In one embodiment, predetermined axial location 308
corresponds to T.sub.max location 204 of fairing 200 that is
positioned within flow passage 306 between upstream end 310 and
downstream end 320 of transition duct 300. In another embodiment,
and with respect to transition duct 400, a predetermined axial
location 408 is located downstream from T.sub.max location 404. As
fluid is channeled substantially axially through transition duct
300, the presence of fairing 200 in flow passage 306 facilitates
creating flow separation therein, particularly at leading edge 202
and downstream from T.sub.max location 204.
[0024] In another embodiment, predetermined axial location 308
corresponds to an axial location within transition duct 300 where
flow separation may become present at the boundary layer of
radially outer wall 302. More specifically, flow separation at the
boundary layer of radially outer wall 302 is caused by the
aggressive outer wall slope. Accordingly, radially outer wall 302
is contoured to facilitate preventing flow separation of fluid
channeled through transition duct 300 with fairing 200.
[0025] In the exemplary embodiment, transition duct 300 facilitates
increasing turbine efficiency while preventing flow separation by
increasing the slope of radially outer wall 302 from upstream end
310 to predetermined axial location 308, and decreasing the slope
of radially outer wall 302 from predetermined axial location 308 to
downstream end 320. As such, in the exemplary embodiment, radially
outer wall 302 has a slope of about 0.degree. at upstream end 310.
The slope of radially outer wall 302 then increases to a maximum
wall slope 324 at predetermined axial location 308, or a maximum
wall slope 424 at predetermined axial location 408. Maximum wall
slopes 324 and 424 are greater than about 40.degree., and more
specifically from about 40.degree. to about 50.degree.. The slope
of radially outer wall 302 then decreases from predetermined axial
location 308 such that the slope of radially outer wall 302 at
downstream end 320 is no less than about 30.degree..
[0026] The transition duct described herein facilitates improving
the performance of a turbine assembly by facilitating reducing flow
separation within a shorter transition duct. The transition duct
described herein uses an aggressive outer wall slope to quickly
transition between a high-pressure turbine and a low-pressure
turbine. However, the quick transition and the presence of
aerodynamic struts that extend radially through the transition duct
may lead to outer wall diffusion and/or flow separation therein. As
such, the curvature and slope of the radially outer wall of the
transition duct is controlled to facilitate reducing flow
separation therein, thereby improving the efficiency of the
low-pressure turbine.
[0027] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *